Pine Diseases Changing Landscapes Forever

Posted on March 30, 2022 by Scott Vogt

The Arboretum continues to change. If you visited the Arboretum in the early years, you would have seen many different types of pine trees and other evergreens planted in groves. These pine trees initially flourished, even though they are not native to Kansas. However, over the past 20 years, the Arboretum has lost many of those original pine trees.

This is not an isolated problem. Whole shelterbelts, specimen trees and screens have been decimated by diseases exclusive to pines. What are the most common pine diseases and what can be done to control their spread? That is a question I’m often asked and there are no easy answers. I do suggest Kansas State Extension and online resources for more information.

Pine Wilt

Pine Wilt threatens to remove several pines permanently from the landscape. Discovered in Missouri in 1979, pine wilt is most serious on Scotch Pines but can infect Austrian and White Pines. Since that initial report, it has continued to move westward and has completely decimated all of the Scotch pines in the Arboretum.

Symptoms for Pine Wilt usually appear from August through December and cause the trees to wilt and die rapidly in a month or two. Trees may survive for more than one year but the result is always fatal. The needles turn from bluish-gray to yellow/brown and remain attached to the tree.

Several organisms play a role in the death of a tree. The pinewood nematode is transmitted from pine to pine by a bark beetle, the pine sawyer. Once inside the trunk, the microscopic worms feed on the blue stained fungi that live in the wood but also on the living plant cells surrounding the resin canals and water-conducting passages, essentially choking the tree. There are no highly effective management tactics. Dead pines should be promptly cut and destroyed before warm weather of spring. If this is not done, beetles can continue to emerge from the logs and infect more trees.

*Austrian Pine dead from disease that will be removed this spring in the Arboretum*

Other Pine Diseases

Foliar diseases such as Sphaeropsis Tip Blight (STB), Dothistroma Neddle Blight (DNB), and Brown Spot of Pines (BSoP) are caused by types of fungi that can infect both the new and old growth. Some of the species affected by these diseases include Austrian, Mugo, Scots, and Ponderosa Pines. The symptoms of STB appear on the current year’s shoots. As the new shoots emerge in the spring, they are susceptible to infection by the fungus. Any damaged area provides the spores a way into the tree. The spores are dispersed by water and require high humidity for germination and penetration of the host tissue. Both DNB and BSoP cause spotting of the needles and eventually premature defoliation. Transmission is again by water and moisture. In a year with many spring rains, the moisture can spread the spores like wildfire and many treatments are needed to keep them in check.

Treatment Options

These three foliar diseases can be treated with multiple applications of copper fungicides and Bordeaux mixtures in the spring and early summer. Treatments are costly and high pressure equipment is needed to project the spray to the top of the trees. It has been my experience that control of these diseases is difficult. Spray timing is critical, densely planted trees are highly susceptible, and infection occurs during excessive rainfall. Thinning trees and removing dead or diseased branches will prolong the life of the tree, but the best defense is to keep the trees healthy by providing adequate moisture and fertility.

Diversity is the Key

One of the key lessons we have learned from this experience is that diversity is vital to a successful landscape. Whether pine trees, deciduous tree, perennials or shrubs, don’t put all your eggs in one basket. Establish a variety of plants adapted to your landscape rather than just one or two species. The truth is that you can do everything right and still lose an evergreen tree. Replant with a diverse variety of species so your whole landscape will not be open to widespread devastation again. There will be other diseases that come, but diversity will give you the edge.

Other Evergreens

New evergreen species are being trialed for adaptability in Kansas, but at this time there are not many viable alternatives other than our eastern red cedar with cultivars such as ‘Taylor’ and ‘Canaertii’. Southwestern White Pine (Pinus strobiformis), Arizona Cypress (Cupresses arizonica), Black Hills Spruce (Picea glauca var. densata) and Pinyon Pine (Pinus edulis) are also viable options. Full descriptions of these trees can be researched on the internet or you can come to the Arboretum and view them in person.

Pines like Ponderosa (Pinus ponderosa), Austrian (Pinus nigra) and Scotch (Pinus sylvestris) have been taken off the recommended tree list because they are so prone to disease. I would highly encourage you to visit the Kansas Forestry Service website at www.kansasforests.org . Once there, choose your region to view a full list of recommended trees for your area along with other informative publications.

Wind-Pollinated Flowers

Posted on March 23, 2022 by Brad Guhr

Social media is blowing up right now with photos of colorful bulb flowers including daffodils, crocuses, and dwarf irises. And why not? Who doesn’t love to see these splashes of color in a drab, brown landscape along sidewalks to stimulate our sights after a long winter?! Nobody, however, seems to be posting photos of the much greater masses of wind-pollinated flowers that have also been blooming and tickling our senses…our nasal passages, that is.

For weeks now, my eyes, nose, and throat have been growing increasingly runny and itchy. From a distance, I’ve been seeing swelling buds on trees, and last week I did some investigation. Sure enough, the first blooming trees (silver maples, red maples, and eastern red cedars) at Dyck Arboretum are in full bloom.

*Silver maple (Acer saccharinum) flowers 3/16/22…do cause allergies*

Insect-pollinated flowers have heavy pollen. They need to attract insects with colorful petals to carry pollen away on their hairy bodies to other flowers. Conversely, wind-pollinated flowers have light pollen that carries easily in the wind once released. They do not need to invest expensive energy on creating large, colorful petals and are thus more visibly obscure.

Airborne pollen also gets deposited in our noses, eyes, and throats. Enough said.

*Red maple (Acer rubrum) flowering 3/16/22*

Eastern red cedar (Juniperus virginiana) flowering 3/16/15 (and the same tree was blooming 3/16/22 as well)

Defining Common Horticultural Terms, Part 2

Posted on March 16, 2022 by Scott Vogt

We encounter many enthusiastic new gardeners at FloraKansas who have heard about the importance of planting native plants, but don’t yet have the knowledge base needed to establish a successful planting. If you’re dreaming of a flourishing prairie pollinator garden, let me unpack the why behind the what of a few more horticultural terms for you.

Host Plants

Often, the focus for our gardens is on blooms and succession of blooms, more so than host plants. Beautiful gardens in full bloom are what we see in catalogs, magazine and books. It is natural to gravitate toward these flourishing gardens that nectar-seeking butterflies need to sustain themselves. However, host plants (food for butterfly caterpillars) will keep them coming back to your landscape for years to come.

It’s important to plan for the entire life cycle of a pollinator. Butterflies need places to lay their eggs. Think of host plants as the baby nurseries of the garden. Female butterflies will flit and flutter through your garden looking for the right plant to lay their eggs. Some will lay their eggs on stems, or on the underside of leaves, hidden from predators. If you have a variety of host plants, you will attract a variety of butterflies.

*Newly hatched monarch caterpillar on common milkweed* *(Photo by Brad Guhr)*

Ultimately, the goal of any habitat garden is to provide everything those butterfly species need to complete their life cycle. Food for all stages of their life cycle, protection, and water are needed at different times throughout the year. The tiny larvae (caterpillars) will emerge and begin eating on the host plant. As they eat, they grow until they leave the plant and form a chrysalis. It is a fascinating process that you can watch unfold in your own garden.

Here are a few host plants and the pollinator they attract:

Wild Lupine – Karner Blue butterfly
Golden alexander – Black Swallowtail butterfly
New Jersey Tea – Spring Azure butterfly
Columbine – Columbine Duskywing
Smooth Blue Aster – Crescent Butterflies
Little Bluestem – Leonard’s Skipper
Prairie Violet – Fritillary Butterflies
Pearly Everlasting – American Lady
Milkweeds – Monarchs
Paw Paw – Zebra Swallowtail butterfly

*Zebra Swallowtail Butterfly on Pawpaw tree at the Arboretum*, *photo by Janelle Flory Schrock*

Resource: Holm, Heather. Pollinators of Native Plants: Attract, Observe, and Identify Pollinators and Beneficial Insects with Native Plants. Pollination Press, 2014.

Sunlight Defined

Knowing how much light you have within your landscape is an important piece to a sound design. By simply watching sun patterns throughout the year, you will be able to determine how much sunlight your garden receives. Industry standards and labeling can then be used to assist in selecting the right plants for your landscape conditions. Here are some terms worth knowing since all plants require sunlight to grow, but differ in the amount and intensity of light needed to prosper.

Full sun – Plants need at least 6 hours of direct sun daily
Part sun – Plants thrive with between 3 and 6 hours of direct sun per day
Part shade – Plants require between 3 and 6 hours of sun per day, but need protection from intense mid-day sun
Full shade – Plants require less than 3 hours of direct sun per day

Full Sun

Not surprisingly, this type of light describes what most prairie plants need. They enjoy open, bright sunny locations with direct sunlight for most of the day. This could also be morning shade/afternoon sun or vice versa, as long as there is at least 6 hours of continuous sunlight. Most of these plants have deeper root systems or adaptations that help them endure this light intensity for the growing season.

Let experience be your guide when situating plants. Yes, some plants can handle full sun, but need protection for the hot afternoon sun. Or they can handle full sun with consistent moisture. This is the other reason to understand your site, including soil moisture, soil type, root competition and drainage. All these factors directly affect plants too.

Part Sun and Part Shade

These light definitions are quite a bit different than plants for full sun. Plants for part sun and part shade obviously require less light, more importantly, the light intensity is a key factor for their endurance and success. Filtered sun for most of the day or morning sun afternoon shade fit the bill for situating plants. Too much direct sunlight for too long a period will stunt plants needing part sun or part shade.

There is often a fine line between getting too much sun that the plants suffer and getting too little light that the plants don’t bloom. For either group, providing direct morning sun is often the best choice.

Full Shade

Most shade plants require anything from the dappled shade found under deciduous trees, indirect light found on the north side of the house or deeper shade found under evergreens. In our area, growing shade plants can be a challenge because we are trying to grow shade plants in what was once a prairie environment with intense full sun. True shade plants often perish because they get too much sun, too much hot dry wind and/or too little moisture.

To successfully grow shade plants in our area, they need protection and consistent moisture. Any shade gardens must mimic the woodland environment. Loamy soils with leaf litter, consistent moisture – but not too much! – and protection from drying winds. It can be a challenge, but shade gardens can be carefully created with the proper light conditions, too.

*Dyck Arboretum woodland garden with columbine, woodland phlox, white woodland aster and solomon’s seal*

All About Asters

Posted on March 9, 2022 by Katie Schmidt

Spring hasn’t even started and I am already looking forward to fall. Why? Asters. They are hardy, long-blooming, and attract tons of pollinators. Planning ahead and planting asters now will ensure you have lots of color through October and even into November. If not now, then by the time they are blooming and you remember how much you like them… it will be too late!

There are lots of great asters available at our biannual Florakansas fundraisers. Sun-loving, shade-tolerant, and a myriad of colors to choose from, it can be overwhelming to decide on a variety. Check out Scott’s previous blog on asters to learn about a great variety of native asters. Here I will cover only those not included in that blog, as well as new varieties available at our upcoming FloraKansas event.

Aster lateriflorus ‘Lady In Black’

*‘Lady In Black’ is quite showy with dark foliage and masses of bright flowers. Photo from Wikimedia Commons.*

Calico aster is a lesser known species, but has a lot of garden potential. The ‘Lady in Black’ variety has dark foliage and white to blush colored flowers with pink centers. It looks great planted in masses, paired with sturdy grasses around it for support like Panicum ‘Northwind’ or ‘Purple Tears’. Its arching stems are graceful, and add a lot of energy and movement to a prairie garden or meadow planting.

Aster sericeus

One of my personal favorites, it is often overlooked for flashier species. Silky aster is diminutive but tough as nails, and its wiry stems offer nice contrast to its light green, hairy leaves. It has a silver tint to it, especially from a distance, so it adds a wonderful cool tone to any hot, sunny place in the garden. It has a somewhat prostrate habit, so it benefits from sturdy plants around it for support. I’d pair this with Schizachyrium ‘Jazz’ or even some old fashioned lambs ear as both would bring out the blueish-silver tone of the foliage.

Silky aster is native throughout the Flint Hills and mixed grass prairie areas.
Map from USDA plants data base.

Aster novae-angliae ‘Grape Crush’

New England asters are known for their late blooms and towering height. As much as they are loved by pollinators, gardeners have come to curse them for becoming too tall and floppy. ‘Grape Crush’ is a shorter, denser variety. It keeps a much tidier habit and has a deep purple color. We will also have ‘Purple Dome’ New England type, which is very similar but perhaps with a slightly earlier bloom time. We are excited to try planting some ‘Grape Crush’ around our grounds this season!

*Aster ‘Grape Crush’, photo courtesy of Walter’s Gardens*

Also available this spring…

Aster nova-belgii ‘Anton Kippenberg’ (a New York type that doesn’t flop, blue flowers in early fall)
Aster ericoides ‘Snow Flurry’ (less than 6″ tall, full sun/dry soil, toughest plant around)
Aster leavis ‘Bluebird’ (full sun, tall and floriferous!)
Aster divaracatus (white flowers, good in shade)
Aster cordifolus (white to bluish flowers, taller than A. divaricatus, good in dry shade)
Aster dumosus ‘Woods Blue’ and ‘Woods Purple’ (very short and compact)

Name Change

Note that many aster species have formally changed their taxonomic name to Symphyotrichum. Due to modern research and genetic study, botanists have found that not all asters belong in the same group, so Symphyotrichum is a new genus name that will help us better understand this huge family of plants. In our native plant guide you will find this name change already in action.

Defining Common Horticultural Terms

Posted on March 3, 2022 by Scott Vogt

There are many horticultural terms that get tossed around in casual conversation. We hear these words or phrases in presentations, and read them in books and seed catalogs. Presenters often assume that everyone knows what they mean without much explanation. Here are a just a few words I use from time to time that I would like to define for you.

Xeriscape

Denver Water coined the term xeriscape in 1981 by combining landscape with the Greek prefix xero-, from (xēros), meaning ‘dry’. Xeriscaping = water-conserving landscapes. This landscaping concept focuses on several water conserving measures such as:

Planning and design that matches plants to the site
Water-efficient plant materials, especially native plants
Efficient irrigation systems including drip irrigation
Use of water-conserving mulch or densely planted gardens
Soil preparation only if necessary
Appropriate turf since it can be very water consuming

Something to remember: a xeric garden can still be a beautiful garden. It will just require less water over time so it’s a win, win situation.

Habitat

A habitat garden is a garden that mimics the natural landscape while also providing food, shelter and potentially water for wildlife, including pollinators. A habitat garden has layers of plants and a succession of blooms. It is a very intentional way of landscaping focused more on giving back rather than taking something from your landscape. Don’t get me wrong, a habitat garden can still be beautiful, but it will certainly give you much more enjoyment as you attract a host of pollinator, birds and other wildlife to your yard.

Stratification

One of the most interesting processes I learned when I first started working at the Arboretum was the process of stratification. It intrigued me that I could collect seed from the wild and get it to germinate in the greenhouse simply by simulating the chilling and warming that seeds would endure if left outdoors for the winter in their native climate. This chilling and warming that seeds are exposed to breaks down natural germination inhibitors until they are ready and able to germinate the next year.

This process is so important for plants and their survival because it keeps seeds from germinating the same year of development. They must go through a cold period such as winter before they are able to germinate. This does two important things: keeps seeds from germinating in the fall and allows the seeds to be worked into the soil over the winter with the natural freeze/thaw of the soil so they can germinate in spring.

If a seed would germinate in the fall, that tiny plant would not have enough time to develop a sustaining root system. The tiny seeding would not survive the winter. The natural process allows a seed to lay dormant all winter and germinated in the spring when conditions are more favorable for survival, it would have the entire growing season to develop a healthy root system.

This process of stratification is why we encourage people to scatter prairie wildflowers and grass seed in November and December. It allows time for this process to occur so the seeds will germinate the following year.

Hopefully, this is helpful. I will discuss some other terms in upcoming blogs.